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Measles outbreak after 12 years without endemic transmission, Portugal, February to May 2017 F George ¹ , J Valente ¹ , GF Augusto ¹ , AJ Silva ¹ , N Pereira ¹ , T Fernandes ¹ , P Palminha ² , BA Aguiar ¹ , A Martins ¹ , E Santos ¹ , P Valente ¹ , E Calé ¹ , A Leça ¹ , PJ Nogueira ¹ 1. Directorate-General of Health, Lisbon, Portugal 2. National Institute of Health Dr Ricardo Jorge, Lisbon, Portugal Correspondence: Paulo Jorge Nogueira ([email protected]) Citation style for this article: George F, Valente J, Augusto GF, Silva AJ, Pereira N, Fernandes T, Palminha P, Aguiar BA, Martins A, Santos E, Valente P, Calé E, Leça A, Nogueira PJ. Measles outbreak after 12 years without endemic transmission, Portugal, February to May 2017. Euro Surveill. 2017;22(23):pii=30548. DOI: http://dx.doi.org/10.2807/15607917.ES.2017.22.23.30548 Article submitted on 30 May 2017 / accepted on 08 June 2017 / published on 08 June 2017
We report a measles outbreak in two Portuguese health regions (Algarve and Lisbon and the Tagus Valley) since February 2017, and which by 31 May resulted in 28 confirmed cases, of which 16 were unvaccinated. Thirteen cases were healthcare workers. One unvaccinated teenager died. Genotype B3 was identified in 14 cases from both regions. This outbreak occurs after 12 years without endemic measles transmission, and in a context of high measles vaccination coverage and immunity. We describe a measles outbreak that started in February 2017, with 28 confirmed cases, as at 31 May. The investigation is ongoing and we present here preliminary findings and the implemented control measures. After the identification of the first measles case, a contingency plan at the Directorate-General of Health (Direção-Geral da Saúde, DGS) was implemented, following the Portuguese National Programme for Measles Elimination (Programa Nacional de Eliminação do Sarampo, PNES) [1]. This report is based on data extracted on 31 May from the National System for Epidemiological Surveillance (Sistema Nacional de Vigilância Epidemiológica, SINAVE), which is an integrated clinical and laboratory system of mandatory notification. Vaccination against measles is included in the national immunisation programme (Programa Nacional de Vacinação, PNV) since 1974 and is available for free. This outbreak occurs after a 12-year period without endemic measles transmission in Portugal, which led the World Health Organization (WHO) Regional Office for Europe to certify measles as eliminated in the country in 2015 and 2016 [2]. In Portugal, measles is a mandatory notifiable disease since 1987 and, within the scope of the PNES [1], any suspected measles case notified is investigated thoroughly.
www.eurosurveillance.org
Immunity against measles is high in Portugal. The National Serological Survey conducted in 2001–02 showed a proportion of immune individuals above 93.4% in all age groups [3]. Preliminary results from the latest survey (2015–16), show that this trend of high immunity was maintained (data not shown).
Case definition
The measles case definition used during this outbreak was based on the European Commission case definition [4]. Measles cases were defined as possible, probable or confirmed, depending on clinical, epidemiological and laboratory criteria. A possible case was any person who met clinical criteria i.e. fever, maculopapular rash, and any of cough/ coryza/conjunctivitis; a probable case was any person who met clinical criteria and had an epidemiological link to a confirmed case; a confirmed case was any possible case with laboratory evidence of infection with measles virus i.e. detection of viral RNA in a biological sample and/or a positive IgM result in serum, determined by the WHO-certified national reference laboratory for measles and rubella (National Institute of Health – Instituto Nacional de Saúde Doutor Ricardo Jorge, INSA) [5]. Following the WHO criteria [6], cases were discarded when clinical, epidemiological or laboratory criteria were not met, taking into account vaccination history and risk of measles infection in the community or abroad.
Outbreak description
As at 31 May, 156 measles cases were notified in Portugal in 2017. In the outbreak reported here, 28 cases were confirmed, seven were classified as possible, three cases were under investigation and 117 cases were discarded. Additionally, one confirmed imported measles case was identified in the north health region, 1
Figure 1 Incidence rate of confirmed measles cases per 100,000 population by health region, Portugal, 23 February–31 May 2017 (n = 28 confirmed cases)
epidemiological investigations that led to the retrospective identification of three additional cases, with prior disease onset. Overall, this transmission chain comprised seven confirmed cases (Figure 1, 2). The earliest case had rash onset on 23 February and the latest had rash onset on 8 April. No further confirmed cases were identified in Algarve. Five of these cases acquired measles in a healthcare setting, including two healthcare workers; five cases (4 infants aged under 1 year and 1 adult) were hospitalised. To date, no epidemiological link has been found between this cluster and other cases reported in Portugal or abroad.
Lisbon and the Tagus Valley health region
Incidence rate per 100,000 population 1,3 to 2,0 0,3 to 0,6 0,0 to 0,3
The first case identified in the LVT health region was reported by a paediatrician from Cascais Hospital to the Regional Department of Public Health and the DGS on 6 April (rash onset on 30 March). Twenty-one cases were confirmed in LVT health region, with the earliest case having had rash onset on 17 March. This case was identified due to the epidemiological investigation of the first notified case in this region. The last confirmed case in the LVT region had developed rash on 13 May and no further measles cases were confirmed. The transmission chain in the LVT region is under investigation, with epidemiological links already identified between most cases. Eleven cases were healthcare workers. In the LVT region, seven cases were hospitalised, and one death has occurred in an unvaccinated teenager.
Characteristics of cases Map developed by GeoSaúde (http://www.geosaude.dgs.pt/). Source: Direção-Geral da Saúde, Sistema Nacional de Vigilância Epidemiológica.
which was an isolated case with no epidemiological or genotypic links to the cases in the outbreak described here. All possible measles cases notified were investigated and control measures were promptly implemented in order to contain transmission. This report focuses on the description of confirmed cases in Algarve and Lisbon and the Tagus Valley (Lisboa e Vale do Tejo, LVT), two health regions which are not in close proximity (Figure 1). The distribution of cases over time is described in the epidemic curve (Figure 2).
Algarve health region
The first measles case was notified to health authorities on 30 March (rash onset on 21 March), and was from the Algarve health region, a touristic region with tourists mainly from other European countries. Local and regional public health teams immediately initiated 2
Most confirmed measles cases (n = 19) occurred in adults (≥ 18 years), two cases were adolescents (10– 18 years), and seven cases occurred in children (
Measles outbreak after 12 years without endemic transmission, Portugal, February to May 2017 F George ¹ , J Valente ¹ , GF Augusto ¹ , AJ Silva ¹ , N Pereira ¹ , T Fernandes ¹ , P Palminha ² , BA Aguiar ¹ , A Martins ¹ , E Santos ¹ , P Valente ¹ , E Calé ¹ , A Leça ¹ , PJ Nogueira ¹ 1. Directorate-General of Health, Lisbon, Portugal 2. National Institute of Health Dr Ricardo Jorge, Lisbon, Portugal Correspondence: Paulo Jorge Nogueira ([email protected]) Citation style for this article: George F, Valente J, Augusto GF, Silva AJ, Pereira N, Fernandes T, Palminha P, Aguiar BA, Martins A, Santos E, Valente P, Calé E, Leça A, Nogueira PJ. Measles outbreak after 12 years without endemic transmission, Portugal, February to May 2017. Euro Surveill. 2017;22(23):pii=30548. DOI: http://dx.doi.org/10.2807/15607917.ES.2017.22.23.30548 Article submitted on 30 May 2017 / accepted on 08 June 2017 / published on 08 June 2017
We report a measles outbreak in two Portuguese health regions (Algarve and Lisbon and the Tagus Valley) since February 2017, and which by 31 May resulted in 28 confirmed cases, of which 16 were unvaccinated. Thirteen cases were healthcare workers. One unvaccinated teenager died. Genotype B3 was identified in 14 cases from both regions. This outbreak occurs after 12 years without endemic measles transmission, and in a context of high measles vaccination coverage and immunity. We describe a measles outbreak that started in February 2017, with 28 confirmed cases, as at 31 May. The investigation is ongoing and we present here preliminary findings and the implemented control measures. After the identification of the first measles case, a contingency plan at the Directorate-General of Health (Direção-Geral da Saúde, DGS) was implemented, following the Portuguese National Programme for Measles Elimination (Programa Nacional de Eliminação do Sarampo, PNES) [1]. This report is based on data extracted on 31 May from the National System for Epidemiological Surveillance (Sistema Nacional de Vigilância Epidemiológica, SINAVE), which is an integrated clinical and laboratory system of mandatory notification. Vaccination against measles is included in the national immunisation programme (Programa Nacional de Vacinação, PNV) since 1974 and is available for free. This outbreak occurs after a 12-year period without endemic measles transmission in Portugal, which led the World Health Organization (WHO) Regional Office for Europe to certify measles as eliminated in the country in 2015 and 2016 [2]. In Portugal, measles is a mandatory notifiable disease since 1987 and, within the scope of the PNES [1], any suspected measles case notified is investigated thoroughly.
www.eurosurveillance.org
Immunity against measles is high in Portugal. The National Serological Survey conducted in 2001–02 showed a proportion of immune individuals above 93.4% in all age groups [3]. Preliminary results from the latest survey (2015–16), show that this trend of high immunity was maintained (data not shown).
Case definition
The measles case definition used during this outbreak was based on the European Commission case definition [4]. Measles cases were defined as possible, probable or confirmed, depending on clinical, epidemiological and laboratory criteria. A possible case was any person who met clinical criteria i.e. fever, maculopapular rash, and any of cough/ coryza/conjunctivitis; a probable case was any person who met clinical criteria and had an epidemiological link to a confirmed case; a confirmed case was any possible case with laboratory evidence of infection with measles virus i.e. detection of viral RNA in a biological sample and/or a positive IgM result in serum, determined by the WHO-certified national reference laboratory for measles and rubella (National Institute of Health – Instituto Nacional de Saúde Doutor Ricardo Jorge, INSA) [5]. Following the WHO criteria [6], cases were discarded when clinical, epidemiological or laboratory criteria were not met, taking into account vaccination history and risk of measles infection in the community or abroad.
Outbreak description
As at 31 May, 156 measles cases were notified in Portugal in 2017. In the outbreak reported here, 28 cases were confirmed, seven were classified as possible, three cases were under investigation and 117 cases were discarded. Additionally, one confirmed imported measles case was identified in the north health region, 1
Figure 1 Incidence rate of confirmed measles cases per 100,000 population by health region, Portugal, 23 February–31 May 2017 (n = 28 confirmed cases)
epidemiological investigations that led to the retrospective identification of three additional cases, with prior disease onset. Overall, this transmission chain comprised seven confirmed cases (Figure 1, 2). The earliest case had rash onset on 23 February and the latest had rash onset on 8 April. No further confirmed cases were identified in Algarve. Five of these cases acquired measles in a healthcare setting, including two healthcare workers; five cases (4 infants aged under 1 year and 1 adult) were hospitalised. To date, no epidemiological link has been found between this cluster and other cases reported in Portugal or abroad.
Lisbon and the Tagus Valley health region
Incidence rate per 100,000 population 1,3 to 2,0 0,3 to 0,6 0,0 to 0,3
The first case identified in the LVT health region was reported by a paediatrician from Cascais Hospital to the Regional Department of Public Health and the DGS on 6 April (rash onset on 30 March). Twenty-one cases were confirmed in LVT health region, with the earliest case having had rash onset on 17 March. This case was identified due to the epidemiological investigation of the first notified case in this region. The last confirmed case in the LVT region had developed rash on 13 May and no further measles cases were confirmed. The transmission chain in the LVT region is under investigation, with epidemiological links already identified between most cases. Eleven cases were healthcare workers. In the LVT region, seven cases were hospitalised, and one death has occurred in an unvaccinated teenager.
Characteristics of cases Map developed by GeoSaúde (http://www.geosaude.dgs.pt/). Source: Direção-Geral da Saúde, Sistema Nacional de Vigilância Epidemiológica.
which was an isolated case with no epidemiological or genotypic links to the cases in the outbreak described here. All possible measles cases notified were investigated and control measures were promptly implemented in order to contain transmission. This report focuses on the description of confirmed cases in Algarve and Lisbon and the Tagus Valley (Lisboa e Vale do Tejo, LVT), two health regions which are not in close proximity (Figure 1). The distribution of cases over time is described in the epidemic curve (Figure 2).
Algarve health region
The first measles case was notified to health authorities on 30 March (rash onset on 21 March), and was from the Algarve health region, a touristic region with tourists mainly from other European countries. Local and regional public health teams immediately initiated 2
Most confirmed measles cases (n = 19) occurred in adults (≥ 18 years), two cases were adolescents (10– 18 years), and seven cases occurred in children (
